AFfilehandle afOpenFile(const char *path, const char *mode,
	const AFfilesetup seutp);

afOpenFile opens a specified audio file and creates a file handle
structure which is used for subsequent calls to the Audio File
Library.

path is the path to the file to be opened.

mode specifies a mode for opening the file (typically "r" or "w").

setup is ignored unless the mode specifies writing.

afOpenFile returns, upon success, a valid AFfilehandle which can be
used in subsequent calls to the Audio File Library for reading or
writing.

Upon failure, afOpenFile returns a null file handle
(AF_NULL_FILEHANDLE).

afCloseFile is used to close the file when it is no longer needed.
